It was a close presidential election last night, but the United States has seen closer. President Obama won a second term, defeating Mitt Romney with more than 300 electoral votes. With Florida still too close call, he was declared the victor in most of the remaining battleground states.

INSKEEP: The president celebrated with supporters in his hometown of Chicago. This afternoon he returns to Washington, where he has promised to work with lawmakers from both parties to tackle some of the big challenges of the next four years.

Here's NPR's Scott Horsley.

SCOTT HORSLEY, BYLINE: President Obama managed to carry nearly every state that he won four years ago, despite stubbornly high unemployment and lingering controversy over some of his initiatives. Mr. Obama told a cheering crowd in Chicago the strong showing is a vote of confidence, with the economy now on the mend and a decade of war drawing to a close.

PRESIDENT BARACK OBAMA: We have picked ourselves up. We have fought our way back. And we know in our hearts that for the United States of America, the best is yet to come.

(SOUNDBITE OF CHEERING)

HORSLEY: Mr. Obama congratulated his Republican rival, Mitt Romney, on a hard-fought campaign. He also thanked the many volunteers who've been working to register new voters, persuade the undecided, and make sure everyone who's eligible to vote got to the polls.

OBAMA: Thank you for believing all the way, through every hill, through every valley.

HORSLEY: The strength of that Obama ground game may have been decisive in several close contests. The winning margins in Ohio, Virginia and Colorado were all around three percentage points or less. The margin is less than one percent in Florida, where for now Mr. Obama has the lead.

As one swing state after another turned blue on the network television maps, Mr. Obama returned to a familiar theme: We're more than a collection of red states and blue states, he said. We are and forever will be the United States.

OBAMA: Democracy in a nation of 300 million can be noisy and messy and complicated. We have our own opinions. Each of us has deeply held beliefs. And when we go through tough times, when we make big decisions as a country, it necessarily stirs passions.

HORSLEY: That won't change, the president said. But as divisive as this election has been, he and Republicans in Congress need to find a way to work with one another. One immediate challenge is the so-called fiscal cliff, a set of tax hikes and spending cuts that almost no one in Washington wants but that's set to take effect automatically in the New Year, unless Congress acts.

Mr. Obama's political advisor, David Plouffe, says the high price of gridlock should get people's attention.

DAVID PLOUFFE: Presidential campaigns are tough. Whenever we're in them, it always seems like the toughest campaign in history. But we've got big challenges and big opportunities. People will dust themselves off and the attention appropriately will turn to that away from politics.

HORSLEY: Mr. Obama pointed to the example set by leaders in New York and New Jersey who've worked across party lines to cope with Hurricane Sandy. He promised to enlist the help of ordinary Americans in pressing Congress to compromise more.

OBAMA: The role of citizen in our democracy does not end with your vote.

HORSLEY: The president and his supporters have sometimes grown frustrated at the slow pace and toilsome politics of change in the last four years. But if the exuberance of the last campaign was replaced by gritty determination in this one, Mr. Obama insists his supporters are no less hopeful or hard-working.

OBAMA: I have always believed that hope is that stubborn thing inside us that insists, despite all the evidence to the contrary, that something better awaits us, so long as we have the courage to keep reaching, to keep working, to keep fighting.

HORSLEY: Mr. Obama's re-election preserves the signature accomplishments of his first term, including health care and financial reform. And it puts him in position to shape future government action on tax policy and immigration.

For months now, the president's supporters have chanted four more years as a kind of challenge to those who would try to unseat Mr. Obama. When they took up the chant last night, it was a simple statement of fact.